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Supporting information
Porous-structured of platinum nanocrystals supported on carbon nanotube
film with super catalytic activity and durability
Xin Xin Huanga,#, Yun Chenb,#, Xiao Xia Wanga, Jian Nong Wanga,*
a Nano-X Research Center, School of Mechanical and Power Engineering, East China
University of Science and Technology, 130 Meilong Road, Shanghai 200237, P. R.
China. Tel: +86-21-64252360. E-mail: [email protected] b School of Materials Science and Engineering, Shanghai Jiao Tong University, 800
Dong Chuan Road, Shanghai 200240, P. R. China. # Co-first authors.
Electronic Supplementary Material (ESI) for Journal of Materials Chemistry A.This journal is © The Royal Society of Chemistry 2015
a
b c
d
Figure S1. CNT film. (a) As-prepared film, (b) its SEM and (c) TEM images, (d) the
film after purification, (e, f) potential cycling for Fe purification. Note the presence of
a low content of Fe particles seen as dark dots before purification and their absence
after purification. (f) is the enlarged rectangular region in (e). The Fe peak became
negligible typically after 15 cycles. Scale bars, 1.5 cm (a), 500 nm (b), 200 µm (c),
and 1 µm (d).
0.0 0.5 1.0 1.5 2.0-2
-1
0
1
2
3Cu
rrent
(mA)
Potential (V) vs. RHE
Fe peak
e
-0.2 0.0 0.2 0.4 0.6 0.8-1.0
-0.5
0.0
0.5
15 th cycle
Curre
nt (m
A)
Potential (V) vs. RHE
Fe peak
1 st cycle
f
Figure S2. Schematic of the electrodeposition system (a) and TEM images of Pt
crystals in the prepared catalyst of Pt/CNTF-1 (b, c).
10 nm
b
c
10 nm
0 100 200 300 400 500 600 700 800 9000
10
20
30
40
50
60
70
80
90
100
110
-16-14-12-10-8-6-4-202468
DSC
(mW
mg−1
)
Wei
ght l
oss
(%)
Temperature ( oC )
Exo
Figure S3. Typical TGA curve. Pt content was about 45 wt.%, and the Pt loading on
RDE was calculated to be 90 µg cm-2, which was close to that measured by the
alternative approach of ICP (Pt/CNTF-2).
Figure S4. ADT results for the catalyst of Pt/CNC. (a, b) TEM images of the CNCs, (c)
TEM image of Pt/CNC catalyst, (d) CVs, (e) ORR polarization curves for various
a
b
0.0 0.2 0.4 0.6 0.8 1.0 1.2
-4
-2
0
2
4
dCurre
nt d
ensit
y (m
A cm
−2)
Potential (V) vs. RHE
10 cycles 1K cycles 2K cycles 3K cycles
0.0 0.2 0.4 0.6 0.8 1.0-5
-4
-3
-2
-1
0
eCurre
nt d
ensit
y (m
A cm
- 2)
Potential (V) vs. RHE
10 cycles 1K cycles 2K cycles 3K cycles
f
c
numbers of potential cycling with a Pt loading of 53 µg cm-2 on the electrode, and (f)
TEM image of Pt/CNC catalyst after 5k cycles. Scale bars, 50 nm (a), 10 nm (b, c), 20
nm (f).
Note that the size of the hollow cages was 20-50 nm with a shell thickness of
3-10 nm. The shell was composed of well-developed graphitic layers. Pt nanoparticles
deposited on CNCs were fine and uniformly dispersed on the outer surfaces of CNCs
and the average size was about 3 nm. Both CVs and ORR polarizataion curves
showed fast catalyst degradation even within the first 1000 cycles. The average size of
Pt was about 10 nm after cycling.
Figure S5. ADT results for the catalyst of Pt/C. (a) TEM image of Pt/C, (b) CVs, (c)
ORR polarization curves for various numbers of potential cycling with a Pt loading of
53 µg cm-2 on the electrode, and (d) TEM image of Pt/C after 3000 cycles. Scale bars,
20 nm (a, d).
Note that the average Pt particle size of this commercial catalyst was about 3.6 nm.
After potential cycling, Pt particles dissolved and redeposited to larger sizes (~9 nm).
Both CVs and ORR polarizataion curves showed fast catalyst degradation even within
the first 1000 cycles.
0.0 0.2 0.4 0.6 0.8 1.0
-5
-4
-3
-2
-1
0 c
Cur
rent
den
sity
(mA
cm
- 2)
Potential (V) vs. RHE
10 cycles 1K cycles 2K cycles 3K cycles
0.0 0.2 0.4 0.6 0.8 1.0 1.2
-4
-2
0
2
4 b
Cur
rent
den
sity
(mA
cm- 2
)Potential (V) vs. RHE
10 cycles 1K cycles 2K cycles 3K cycles
0.74 V
OHads
a
d
Figure S6. TEM images of Pt/CNTF-1 catalyst after 8000 ADT cycles. Scale bars,
200 nm (a) and 20 nm (b).
a
b
Figure S7. ADT results for Pt/CNTF-1 catalyst. (a, c, e) A set of the
rotation-rate-dependent current-potential curves, and (b, d, f) Koutecky-Levich plots
at various potentials after 1k, 3k, and 5k cycles.
0.08 0.10 0.12 0.14 0.16
1.0
1.2
1.4
1.6
1.8
2.0
2.2
2.4
2.6
2.8
i−1 (m
A−1)
ω−1/2 (rad−1/2s1/2)
0.65V 0.7V 0.75V 0.775V
(b)Pt/CNTF-11k cycles
0.08 0.10 0.12 0.14 0.16
1.0
1.2
1.4
1.6
1.8
2.0
2.2
2.4
2.6
(d)Pt/CNTF-13k cycles
i−1 (m
A−1)
ω−1/2 (rad−1/2s1/2)
0.65V 0.7V 0.75V 0.775V
0.08 0.10 0.12 0.14 0.16
1.01.21.41.61.82.02.22.42.62.83.03.2
i−1 (m
A−1)
ω−1/2 (rad−1/2s1/2)
(f)Pt/CNTF-15k cycles
0.65 V 0.70 V 0.75 V 0.775 V
0.0 0.2 0.4 0.6 0.8 1.0-1.2-1.1-1.0-0.9-0.8-0.7-0.6-0.5-0.4-0.3-0.2-0.10.00.10.2
(a)
i (m
A)
Potential (V) vs. RHE
1600
1225900625400 rpm
Pt/CNTF-11k cycles
0.0 0.2 0.4 0.6 0.8 1.0-1.2-1.1-1.0-0.9-0.8-0.7-0.6-0.5-0.4-0.3-0.2-0.10.00.1
(e)
i (m
A)
Potential (V) vs.RHE
1600
1225900625
400 rpm
Pt/CNTF-15k cycles
0.0 0.2 0.4 0.6 0.8 1.0-1.2-1.1-1.0-0.9-0.8-0.7-0.6-0.5-0.4-0.3-0.2-0.10.00.10.2
(c)
i (m
A)
Potential (V) vs.RHE
1600
1225
900625
400 rpm
Pt/CNTF-13k cycles
Figure S8. ADT results for commercial Pt/C and Pt/CNTF catalysts. (a) A set of the
rotation-rate-dependent current-potential curves, (b) Koutecky-Levich plots at various
potentials for Pt/C catalyst before ADT cycling, (c) Kinetic current (ik) versus cycling
number for Pt/C and Pt/CNTF-1 with 53 μg cm-2 of Pt loading for the case of 0.7 V,
and (d) Plots of area-specific activity (As) versus cycling number for the case of 53 μg
cm-2 Pt loading.
0.08 0.10 0.12 0.14 0.16
1.0
1.2
1.4
1.6
1.8
2.0
2.2
2.4
2.6
2.8
3.0
(b)Pt/C
ω−1/2 (rad−1/2s1/2)
i−1 (m
A−1)
0.65 V 0.70 V 0.75 V 0.775 V
0.0 0.2 0.4 0.6 0.8 1.0-1.2
-1.0
-0.8
-0.6
-0.4
-0.2
0.0
0.2i (m
A)
Potential (V) vs.RHE
400 rpm
625900
1225
1600
Pt/C
(a)
0 1000 2000 3000 4000 50000.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
Cycling number
Spec
ific a
ctivi
ty A
s (m
A cm
Pt−2
)
Pt/CNTF-1 (53 µg cm-2) Pt/C (53 µg cm-2)
(e)
0 1000 2000 3000 4000 50000
1
2
3
4
5
6
7
Kine
tic c
urre
nt i k
(m
A)
Cycling number
Pt/CNTF-1 (53 µg cm-2) Pt/C (53 µg cm-2)
(c)